Inner cushions for helmets

ABSTRACT

For the present we register a hybrid Inner Cushion for Helmets based on a Composite Foam sandwiched between two foils. The cushions or paddings used in the last century by helmets manufacturers (mainly made with expanded polystyrene, EPS or expanded polypropylene, EPP) absorb impacts by elastic deformation of the material, producing a significant bounce back after being compressed. The composite foams of the present invention avoid the ‘bounce back on head’ effect by converting a large fraction of the incoming kinetic energy in plastic deformation of the material. Thus, the ‘bounce effect’ or ‘counter-coup lesions’, which largely enhance the first impact brain damage, can be greatly reduced. Two covering foils, either made by a metal (i.e. aluminum) or a combination of a metal and a polymer (i.e. mylar), protect the cushion material against environment and other eventual damaging agents. Furthermore, in order to verify the integrity of the cushion after an impact, some testing procedures have been envisaged, such as the electrical capacitance produced by the two covering foils, which will largely depend on their separating average distance and on the dielectric constant of the inner part of the cushion.

TECHNICAL FIELD

[0001] The present invention proposes an Inner Cushion (IC) for helmets having a shock absorbing padding consisting of either an inorganic (i.e. containing silica aerogel) or organic (i.e. containing carbon aerogel, an RF aerogel, a viscoelastic polymer foam, etc.) composite foam, mixed with other Organic or Mineral Foam and an external metal or metal-polymer foil protector in both sides.

BACKGROUND OF THE INVENTION

[0002] The majority of helmet manufacturers utilize EPS (Expanded Polystyrene) or EPP (Expanded Polypropylene) materials for absorbing impacts. Those materials provide a good kinematic behavior in the head deceleration, but from the dynamic point of view, the stored energy in the elastic material will be returned to the deforming agent, i.e. the head, producing further damages to the brain.

[0003] Two common causes of brain damage are head wounds and severe blows to the head. Head wounds describe wounds which actually extend into the brain itself, such as might be the case if a person was shot in the head or if they suffered a crush in part of the skull in an accident. If the skull becomes broken then the brain is vulnerable to direct damage, this is an open head injury. Alternatively, the brain may become damaged even if the skull remains intact if the head receives a very severe blow—a closed head injury. In such cases the damage can be both from the direct strike against the inside of the skull (coup) or from the resulting forces of rotation which cause the brain to strike against the skull at the opposite side of the head (countercoup). These two types of injuries constitute the two most common causes of brain damage in young adults (often resulting from car or motorbike accidents). A further complication of closed head injury is the fact that local neurons tend to develop edema where neurons close to the site of injury swell, retain fluid and become less excitable.

[0004] A head impact, depending on the deceleration, on the shape of the impacting agent or the presence of a protecting helmet, can follow with a perforation or not of the skull. Thus, it can be an immediate damage as the cranial fracture and direct brain injures. But, on the other hand, there are lots of damaging effects produced but further accelerations undergone by the brain until the whole body becomes completely stopped. These subsequent translations, rotations and distentions produce tears, slippings, squashings and other destroying injures in the brain. These injuries subsequently can give rise to vein squashings, cellular damage, haemorrhages and isquemia. The final edema generates in few days a brain necrosis in the surrounding area of the first impact, even with the best treatments (i.e. citicoline). It's the opinion of the best specialists on craneo-encephalic traumatisms that brain damage due to ‘bounce effects’ are even more important than those ones produced by the first impact. It should be pointed out that preserving any small part of the brain from damage implies a considerable improvement in the life quality of the accident victims. We should not forget the huge social and sanitary costs of treating and maintaining persons with reduced brain activity.

SUMMARY OF THE INVENTION

[0005] The present invention proposes the utilization of composite foams, as those made with aerogels, in helmets to take up (better than store and release) kinetic energy and eliminate the ‘bounce back on head’ effect. These foams, sandwiched between protecting foils, constitute the core of Inner Cushions which fill the gap between the head to be protected and the external outer shell.

[0006] It's the purpose of this invention to provide a method to absorb the impact energy by using a stiff inner cushion consisting mainly of a mechanically inelastic material.

[0007] The absorbing impact energy materials referred in this invention use two different mechanisms to convert kinetic energy into heat:

[0008] a) Crushing of the structure of the material, i.e. silica aerogel is like foamed glass, the collapse of the dentritic structure surrounding pores needs lot of energy, finally converted in heating the crushed material.

[0009] b) Diffuse air in the intricate network of pores, i.e. silica aerogels contain an open network of pores in the mesopore range, the fast diffusion of air through the pore network during the collapsing of the material generates turbulences in the microscopic scale converting kinetic energy in heated air.

[0010] It's also a purpose of this invention to protect the filling materials of the cushion by two covering foils made either by a metal, i.e. aluminum, or a metal-polymer film, i.e. mylar.

[0011] It's also a purpose of this invention to provide possible methods to establish the integrity of the stiff inner cushion, i.e. testing the electrical capacitance of the protecting foils, which is related with the average distance between the foils and the dielectric performance of the cushion containing material.

[0012] It's also a purpose of this invention to provide a fire-resisting inner padding, which could protect even at temperatures as high as 500° F. with a suitable flame resistance lining material.

[0013] The purpose of this invention is to provide inner cushions for helmets with-lower or equal weight than those existing in the market.

[0014] From the medical point of view, the purpose of this invention is to improve the protecting performance of the existing helmet cushions, mainly made with expanded polystyrene and expanded polypropylene, by using composite foam materials as fillers which finally reduce the bounce back on head effects such as diffuse axonal injuries, hypoxia, isquemia, blood vessels shearing and others damaging brain effects derived from head impacts.

[0015] The purpose of this invention is to improve the coma values in the Glasgow scale of head injured victims and allow a better quality of life in the post-traumatic period.

[0016] The purpose of this invention is also to adapt the mechanical properties of the cushion and its density by varying the materials composition depending on the expected application of the helmet, in particular in relationship with the maximum deceleration envisaged, i.e. bikes, skates, motorbikes, racing cars.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is an perspective sectional view of a IC (Inner Cushion) according to a first embodiment of the present invention.

[0018]FIG. 2 is an perspective view of the micro-mechanism of the system to check The IC

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] As shown in FIGS. 1 and 2, a Inner Cushion has, for instance, a shell (1) made of aluminum foil and a shock absorbing padding (4) of Silica or Carbon Aerogel (6) fitted between the inner side of the shell (1) and the outer side of the shell (3). The shock absorbing cushion has a foamized or expanded material (5) who keeps all the different parts of the inner cushion bonded.

[0020] The IC of the present embodiment is constructed to protect the head of a wearer. Therefore, when the impact hits the helmet and reach the IC from the outside part, the impact energy is absorbed by the filler materials.

[0021] The IC (1) has two shells (1) and (2) and a shock absorbing padding of Silica Aerogel, Carbon Aerogel or other energy absorbing material (6) with an expanded or foamized material (5) fitted and stuck on a inner and outer side of the shells (1) and (2)

[0022] The IC has an adhesive strip outside of the shells and between of the shells in order to preserve the IC compact and secure.

[0023] The IC has a box (3) system to check in pannel (9) the capacitance by press the button (7) and place the jacks (4) into the IC metal foils.

[0024] Although there have been described what are the present embodiments of the invention, it will be understood by those skilled in the art that variations and modifications may be made thereto without departing from the gist, spirit or essence of the invention. The scope of the invention is indicated by the appended claims.

[0025] In the above embodiment, the present invention is applied to the full-face type helmet (10). Alternatively, the present invention can also be applied to helmets of other types, i.e., a jet-or semijet-type helmet, or a full face-type helmet serving also as a jet-type helmet. It could also be applied to impact-absorbing seats or to energy-absorbing materials placed between the driver's seat and the chassis in racing cars. 

The claims are:
 1. An Inner Cushion having a shock absorbing composite sandwiched between two protecting foils. The composite padding consists of at least one absorbing material acting as an impact energy absorber by at least one of the following mechanisms: i) crushing of the material structure, ii) air diffusing in the pore network.
 2. An Inner Cushion as mentioned in claim 1, where an expanded or foamized material is mixed with Silica Aerogel or Carbon Aerogel or any other aerogel type material to constitute the shock absorbing filler.
 3. An Inner Cushion as mentioned in claim 1, where EPS (Expanded Polystyrene) is mixed with Silica Aerogel, Carbon Aerogel or any other aerogel type material.
 4. An Inner Cushion as claimed in claim 1,where EPP (Expanded Polypropylene) is mixed with Silica, Carbon Aerogel or any other aerogel type material.
 5. An Inner Cushion as mentioned in claim 1,where EPE (Expanded Polyethylene) is mixed with Silica, Carbon Aerogel or any other aerogel type material.
 6. An Inner Cushion as mentioned in claim 1, where MPS (Molded Polystyrene) is mixed with Silica Aerogel, Carbon Aerogel or any other aerogel type material.
 7. An Inner Cushion as mentioned in claim 1,where MPP (Molded Polypropylene) is mixed with Silica or Carbon Aerogel or any other aerogel type material.
 8. An Inner Stiff Cushion as mentioned in claim 1,where MPE (Molded Polyethylene) is mixed with Silica or Carbon Aerogel or any other aerogel type material.
 9. An Inner Cushion as claimed in claim 1,where a Foamed Polyurethane is mixed with Silica or Carbon Aerogel or any other aerogel type material.
 10. An Inner Cushion as claimed in claim 1,where a Foamed Magnesium Silicate is mixed with Silica or Carbon Aerogel or any other aerogel type material.
 11. An inner Cushion as claimed in claim 1,where a Foamed Magnesium Oxychloride is mixed with Silica or Carbon Aerogel or any other aerogel type material.
 12. An Inner Cushion as mentioned in claim 1,where a Foamed Phenolic Foam is mixed with Silica or Carbon Aerogel or any other aerogel type material. 